The majority of spinal cord lesions observed in prostate cancer are related to extradural compression. Intradural (extramedullary or intramedullary) metastases are very rare. The authors report a case of probable carcinomatous myelitis secondary to prostate cancer in a 50-year-old man, 9 months after the initial diagnosis of advanced metastatic prostate cancer. Despite endocrine therapy initiated immediately after diagnosis, the patient rapidly developed leg pain due to vertebral osteolysis. He developed flaccid paraplegia despite radiotherapy of the lumbar spine combined with corticosteroid therapy and chemotherapy. Spinal cord magnetic resonance imaging (MRI) showed typical features of very probable carcinomatous myelitis in the cervicothoracic zone. The patient died shortly after without histological confirmation. Regardless of the primary cancer, intramedullary spinal cord metastases have a very poor prognosis. Based on a literature search, this case appears to be the first case related to prostatic cancer reported in the medical literature.